On Sept. 16, 1982, Neil Swartz, a computer scientist at CMU, posed a
physics problem to his computer science colleagues on the department’s
“bboard,” a form of early online message board similar to today’s
Facebook group. Bboard users often posted science puzzles for one
another to solve and had been discussing the riddle of whether a canary
could fly in an elevator during free fall.

Swartz presented a new scenario, which involved a lit candle mounted on an elevator wall and a drop of mercury on the floor.

“Because of a recent physics experiment, the leftmost elevator has
been contaminated with mercury,” Gayle wrote. “There is also some slight
fire damage. Decontamination should be complete by 08:00 Friday.”

Despite posts noting that the warning was meant in jest, some people
apparently took the notice at face value, believing a mercury spill had
actually taken place. Various bboard users began joking about different
symbols that could identify posts that weren’t meant to be serious.

Eventually, Scott Fahlman, then a computer science research assistant
professor, proposed using :-) for joke posts—or, given the
preponderance of joke posts, simply using :-( for serious ones.

There ya go! And there are still people who question the value of physics??!!